NB-IoT over nRF9160

[Joao Filipe]

Hi

I have some doubts about NB-IoT and I wanted to clarify them before start deeping developing with nRF91 since this module work with this network.

I know that NB-IoT transmits data over LTE, and it could be done within 3 tipes: stand alone, in band, guard band.

I found too that NB-IoT has the range of +-15 km. And this is confusing me because if it transmits over LTE, why only that range.

I know that if the operators want to deploy NB-IoT, they have to install it in they cell towers. It has something to be with that? That means that every cell tower that can receive NB-IoT only can retransmit over  15 km?

If i want to transmit data over nRF9160 with NB-IoT that means that I can only transmit until 15 km from the board? What should I do if I want the board to be in someplace more extreme, more faraway from the population.

Sorry if the question is a little bit irrelevant for you guys.

[MJD093]

Whilst you are right about the three different modes of NB-IoT, they are for the network operator to decide how they implement NB-IoT on their network and are not going to affect the range of the technology. I have also seen NB-IoT ranges boasted of 35km in some articles

Stand-alone mode utilises one or more GSM carriers set to the narrowband spectrum. Stand-alone is usually implemented in areas where cellular services are not present or have been decommissioned (such as GSM). (VIAVI Solutions Inc., 2017)

Guard-band mode is for instances where cellular services are present but NB-IoT is implemented into the guard band of the LTE network. NB-IoT is not allocated LTE resources and avoids possible interference with the LTE service. (VIAVI Solutions Inc., 2017)

In-band mode happens when NB-IoT is positioned in the LTE carrier, thus sharing its resources. This mode is the most cost effective and seamless to implement for mobile network operators as there is no need for hardware changes of the radio equipment and efficiently utilises the spectrum resources for LTE or NB-IoT based on the demand within the network. (VIAVI Solutions Inc., 2017)

As for your concerns over the range, range is determined by many different factors like geography but LPWANs generally have longer range in rural areas that are away from built up areas (cities of concrete). If you have a specific location you wish to use a device at, then the best thing would be to contact the local NB-IoT provider you intend to use and see if they can share some information about the cellular coverage in that area. Alternatively, you could just go there and test the network connection yourself in that specific location.

You can never guarrentee your device will be in cell range, the fact that there are 3G and 4G blindspots in the world are a testament to the patchy nature of cell coverage. The best you can do is try it in the place you want it to be used and measure the RSSI of the device to the cell towers. There are a couple AT commands that the nRF9160 have in the AT manual that can allow you to measure the RSRP of the connected tower and check the RSRPs of any detected neighbouring cells.

Please note however, just because there is LTE coverage does not mean that the cell towers have been upgraded to support Cat-M1 or Cat-NB.

NB-IoT is designed to offer deep-pentration coverage, so it should preform better than standard LTE, especially in structures and underground.

[Joao Filipe]

Wow, thank you for that complete response. I was mistaken, thinking that only because NB-IoT transmits over LTE, that the coverage was worldwide, like i NB-IoT has no  range, like cellular networks. So, if I want to deploy some applications for rural areas, or more extreme ones, transmitting from there, I have to be in that range of <30 km to receive the data right? But one thing we can do is transmit that data collected from the module to a gateway and motorize it from more faraway distances right, more than that 30 km?

Thank you for the first response and if possible this one